MARKETING Big Brother's Pricey Advice:

TRW, whose computerized credit reports document in exquisite detail the bill- paying habits of 143 million consumers, is running TV ads in New York City and Los Angeles that offer people a peek at their own credit reports. For a $35 annual fee, subscribers get a summary of their TRW files and written notice whenever anyone orders a credit check on them.

Since starting the service a few years ago, TRW has persuaded 600,000 cautious customers to sign up. But privacy experts point out that TRW is selling information that federal law requires it to provide for $2 to $15, depending...